Over Billing by Mweb, terrible customer service

Mweb have been over billing me for the last 3 months, i have spent more than 90min on the phone trying to sort this out, no feedback what so ever, i even wrote a query on their website, i have been billed for 2 LTE products, where as i only have one, the other one was cancelled end of Nov 2018, when i took the new Lte contract, i am a very unhappy customer at present, as it seems that Mweb do not care about their customers at all, they just want to debit your account, no matter what, but getting back to a client is an impossible task. Why should i as the customer pay for a non existing service.